This　paper　investigates　the　tribological　behaviors　of　NCF　3015　valve　steel　treated　by　aging　process　(AP)　and　solution　aging　process　(SAP)　at　elevated　temperatures.　The　results　showed　that　SAP　treatment　made　the　gamma＇　phase　dispersed　and　precipitated　in　the　matrix,　which　improved　the　thermostability　and　increased　the　ductile-brittle　transition　temperature.　In　addition,　SAP　promoted　the　formation　of　the　spinel　oxide　structure　with　lubrication　effects　to　improve　the　tribology　properties　of　NCF　3015　valve　steel.　The　coefficient　of　friction　between　SAP-treated　sample　and　ST30　seat　was　smaller.　In　addition,　the　wear　rate　of　SAP-treated　sample　was　lower　than　AP-treated　sample　from　500　to　700　degrees　C.　The　oxide　film　had　an　important　influence　on　the　mechanical　mixing　process　during　the　sliding　wear.　The　wear　mechanism　changed　from　a　mixed　wear　mechanism　composed　of　abrasive　wear,　tribo-oxidation　and　material　transfer　at　500　degrees　C　to　tribo-chemical　reactions　at　600　degrees　C　and　delamination　(surface　fatigue)　at　700　degrees　C.　The　increase　in　the　brittleness　and　the　decrease　in　the　hardness　on　the　surface　could　not　effectively　absorb　the　impact　energy　formed　by　sharp　micro-particles,　which　made　the　delamination　phenomenon　to　be　more　apparent.